1. Field of the Invention
The present invention relates to a novel method for reducing the allergenicity of psyllium seed husk by treating the psyllium seed husk with an enzyme.
2. Discussion of the Background
Psyllium is a known mucilaginous material which has been used extensively in bulk laxatives. More recently, psyllium has been found to have a hypocholesterolemic effect if ingested by humans and animals.
The source of psyllium is the seeds from the plants of the Plantago genus, which grows in certain subtropical regions. The seeds are dark brown, smooth, boat-shaped and shiny. Since it is believed by those skilled in the art that the active ingredient of psyllium is the psyllium seed gum, which is located primarily in the seed husk, present technology uses the ground seed husk as a source for psyllium.
Generally, psyllium seeds are coarsely ground with crude grinding equipment in India and subtropical regions where the psyllium seeds originate, in an attempt to separate the outermost husk material from the underlying pigmented seed coat layer of the psyllium seeds. In this crude grinding process, particles of various size from these layers are mixed with one another as a function of the grinding process. Because of the type and condition of the grinding equipment and variability in the physical dimensions of the psyllium seeds themselves, it is common to have discrete pieces of seed coat mixed in with husk material.
Various methods and apparatus for obtaining high purity mucilage or husk material from psyllium seeds have been proposed. For example, U.S. Pat. No. 4,813,613 discloses a complex apparatus for producing powdered psyllium seed husk including a plurality of impact grinding steps.
Psyllium compositions have been incorporated into food products for many years (J. K. C. Chan, V. Wypyszyk, Cereal Foods World, 1988, 33: 919-922). Such food products include cookie compositions containing flours, sugars, oils, etc, dry mixes for the preparation of baked goods, particularly muffins, psyllium containing dietary aids, and ready-to-eat cereal.
Exposure to psyllium seed husk powder can cause IgE sensitization and IgE-mediated allergic reactions in sensitized individuals (J. D. Bardy, J. L. Malo, P. Seguin, Am. Rev. Respir. Dis., 1987, 135 1033-1038). Most allergic reactions occur following ingestion of psyllium products, in particular, psyllium-containing bulk laxatives (J. S Seggev, K. Ohta, W. R. Tipton, Ann. Allergy, 1984, 43:325-326)
The psyllium seed comprises a substantially centrally located germ, an endosperm surrounding the germ, a relatively thin colored seed coat (bran) surrounding the endosperm and a husk surrounding the colored seed coat. A protein extract containing allergenic proteins can be obtained by extraction of the husk containing the proteins.
It has now been discovered that the seed coat material from psyllium seeds, in general, is high in specific protein fractions which contain allergens. As noted above, it is common to have discrete pieces of the seed coat material mixed in with coarsely ground psyllium seed husk. The present invention provides a novel, convenient and simple method for treating coarsely ground psyllium seed husk to decrease the allergenicity of the seed husk. The process of the present invention directly treats psyllium seed husk compositions to produce a psyllium seed husk which retains its food quality characteristics and yet has reduced allergenicity.